Diagnostic article Generic OBD-II
P2C01: Fuel regulator D control effort outside its plausible range
P2C01 monitors the filtered high-pressure controller output, which differs from simply checking actual rail pressure.
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Documented application
2025 GM 07A-2 documented monitor only; module and calibration applicability must be matched to the vehicle. The application-matrix filename join remains unresolved; no model or engine fitment is inferred.
The code alone does not identify a failed part or establish that a vehicle is safe to drive. Confirm the vehicle, reporting module and applicable service procedure.
P2C01 is a high-pressure fuel-system plausibility check in the source. Its principal quantity is the filtered controller output, expressed in pressure units. This is not the same quantity as the rail-pressure sensor reading, so the code cannot be interpreted by comparing actual pressure with a single fixed maximum.
Positive and negative control limits
One path detects controller output above 7.5 MPa for ten seconds. A second detects output below minus 7.5 MPa for ten seconds. The positive branch also lists a six-second variant when the fuel tank is empty or at reserve. Tank state can therefore affect the documented qualification even when the monitored control limit is unchanged.
The common conditions require a plausible rail-pressure sensor, appropriate post-start operation and active regulation rather than a reset state. The detailed pump, injection and synchronization conditions continue across pages. They must be considered before treating an uneventful idle period as a completed test.
Preserve controller effort and measured pressure separately
If the diagnostic tool exposes them, capture the controller output, rail-pressure setpoint, measured pressure and fuel-level state together. A large corrective demand and a large actual pressure error are related but different observations. The adjacent pressure-deviation codes use a different measured quantity.
The table does not prove a failed regulator or pump. High-pressure fuel work requires the exact service procedure and appropriate equipment; the control-output limits are not physical pressure-test instructions. Verification should reproduce an eligible regulation interval and confirm the relevant branch no longer fails.
Source and applicability
2025 GM 07A-2 documented monitor only; module and calibration applicability must be matched to the vehicle. The application-matrix filename join remains unresolved; no model or engine fitment is inferred. GM PDF, page 717. GM PDF, page 718. GM PDF, page 719. GM PDF, page 720.
Article source documents
Source checks describe how the text was prepared; they do not certify a diagnosis or confirm compatibility with every vehicle using this code.
Original code reference
Dictionary definition
Fuel Pressure Regulator D Performance
This definition retains its original catalog scope. The article above is limited to its explicitly documented application.
Reference scope
Generic OBD-II definition.
A manufacturer label does not establish the model, year, engine or module to which a diagnosis applies. Read the safety and diagnostic limits.
Definition source
- DTC Database: pinned community code definitions
Source checked · MIT